Immune checkpoint inhibitor-related colitis assessment and prognosis: can IBD scoring point the way?

Immune checkpoint inhibitors (ICI) improve survival but cause immune-related adverse events (irAE). We sought to determine if CTCAE classification, IBD biomarkers/endoscopic/histological scores correlate with irAE colitis outcomes. A dual-centre retrospective study was performed on patients receiving ICI for melanoma, NSCLC or urothelial cancer from 2012 to 2018. Demographics, clinical data, endoscopies (reanalysed using Mayo/Ulcerative Colitis Endoscopic Index of Severity (UCEIS) scores), histology (scored with Nancy Index) and treatment outcomes were analysed. In all, 1074 patients were analysed. Twelve percent (134) developed irAE colitis. Median patient age was 66, 59% were male. CTCAE diarrhoea grade does not correlate with steroid/ infliximab use. G3/4 colitis patients are more likely to need infliximab (p  grade 1 CTCAE disease, and demonstrate the potential prognostic utility of objective histologic scoring.